instance method
Module#class_eval
(::String arg0, ?::String filename, ?::Integer lineno) -> untyped
[U] () { (self m) [self: self] -> U } -> U
mod.class_eval(string [, filename [, lineno]]) → obj
mod.class_eval {|mod| block } → obj
vm_eval.c
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static VALUE
rb_mod_module_eval_internal(int argc, const VALUE *argv, VALUE mod)
{
return specific_eval(argc, argv, mod, FALSE, RB_PASS_CALLED_KEYWORDS);
}
Alias of #module_eval
Evaluates the string or block in the context of mod, except that when a block is given, constant/class variable lookup is not affected. This can be used to add methods to a class. module_eval returns the result of evaluating its argument. The optional filename and lineno parameters set the text for error messages.
Example
class Thing end a = %q{def hello() "Hello there!" end} Thing.module_eval(a) puts Thing.new.hello() Thing.module_eval("invalid code", "dummy", 123)
produces:
Hello there!
dummy:123:in `module_eval': undefined local variable
or method `code' for Thing:Class